The phrase comes from everyday spoken Portuguese, where guris is a regional term for kids or young people, especially in southern Brazil, and eu to de olho means I am keeping an eye on you. As a short voice clip it circulates online mainly as a reusable reaction rather than as a quote tied to one scene. People share it in chats and short videos when someone needs a light telling off, and its familiar everyday wording is why it still works without any extra context or explanation.